Polishing machine

ABSTRACT

A polishing machine load plate unit to which workpieces are affixed for polishing, and through which a liquid is selectively circulated.

United States Patent [72] Inventors Stephen A. Boettcher Deerfield(Riverwoods); Louis F. Simonetti, Morton Grove, Ill. [21 1 Appl. No.776,023 [22] Filed Nov. 15, 1968 [45] Patented May 25, 1971 [73]Assignee Speedfam Corporation Des Plaines, Ill.

[54] POLISHING MACHINE 7 Claims, 8 Drawing Figs.

52 U.S.Cl 51/131, 51/266 [51] Int.Cl B24b7/04 [50] FieldofSearch 5l/l31,165.30, 266, 277, 322

[56] References Cited UNITED STATES PATENTS 698,126 4/1902 Miskolczy51/266 2,998,680 9/1961 Lipkins 51/131 3,110,988 11/1963 Boettcher....51/131 Primary Examiner-Lester M. Swingle Attorney-Johnson, Dienner,Emrick, Verbeck & Wagner ABSTRACT: A polishing machine load plate unitto which workpieces are afiixed for polishing, and through which aliquid is selectively circulated.

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Qi aa PATENTEU M25 1971 SHEET 3 OF 3 BACKGROUND OF THE INVENTION 1.Field of the Invention The present invention relates generally to apolishing machine comprised of a rotatable polishing wheel assembly, andmeans for urging workpieces to be polished into engagement with theupper surface of the polishing wheel assembly.

2. Description of the Prior Art One type of polishing machine comprisesa horizontal rotatable backing wheel, a polishing cloth extending acrossthe upper surface of the backing wheel, a load plate unit adapted toreceive workpieces at the lower surface thereof and to be positionedover the backing wheel with the workpieces engaging the polishing cloth,and means, including a vertical spindle assembly, for centering andapplying pressure to the load plate unit. Conventionally, a plurality ofworkpieces to be polished are affixed, for example by parafiin, to thelower surface of the load plate unit. In this manner, the workpieces aremaintained in position relative to the load plate unit, and are movabletherewith, during the polishing operation.

With reference to the foregoing arrangement, dissipation of heatgenerated in the load plate unit during the polishing operation has notbeen entirely satisfactory in all applications; and mounting ofworkpieces to, and removal of the same from, the load plate unitoccasionally has not been as convenient as might be desired.

SUMMARY OF THE INVENTION In accordance with the present invention, theload plate unit is provided with a central upwardly directed opening,and with passageway means communicating with the opening to accommodatecirculation of a fluid coolant interiorly of the unit. Cooperatively,the spindle assembly is provided with fluid transmission means forseparately directing to the opening fluid coolant and receiving from theopening coolant which has absorbed heat. In this manner, the load plateunit is cooled to compensate for heat developed therein during thepolishing operation.

Additionally, the load plate unit is detachable from the spindleassembly; and, at a location remote from the polishing machine, a fluidof suitable temperature may be circulated through the load plate unitfor selectively heating or cooling the same to effect softening orsolidification of the mounting medium as may be required while theworkpieces are being affixed to or removed from the load plate unit. Inthis manner, mounting of workpieces to, and removal of the same from,the load plate unit are greatly facilitated.

BRIEF DESCRIPTION OF THEDRAWINGS FIG. 1 is an elevational view, withportions being broken away and shown in section, of a polishing machineincorporating the principles of the present invention;

FIG. 2 is a horizontal view, taken substantially along the line 22 inFIG. 1, looking in the direction indicated by the arrows;

FIG. 3 is a vertical median sectional view, on an enlarged scale, of theload plate unit and spindle assembly of the present invention, and ofother machine components associated therewith;

FIG. 4 is a horizontal view, taken substantially along the line 4-4 inFIG. 3, looking in the direction indicated by the arrows;

FIG. 5 is a horizontal view on a reduced scale, taken substantiallyalong the line 5-5 in FIG. 3, looking in the direction indicated by thearrows;

FIG. 6 is a foreshortened front elevational view, with portions beingbroken away and shown in section, of a workpiecemounting device;

FIG. 7 is a side elevational view, on a reduced scale, of theworkpiece-mounting device of FIG. 6; and

FIG. 8 is a horizontal view on a reduced scale, taken substantiallyalong the line 8-8 in FIG. 6, looking in the direction indicated by thearrows.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1, thereis indicated generally by the reference numeral 10 a polishing machineincorporating the principles of the present invention. The polishingmachine 10 comprises a framework including a substantially cylindricalhousing 12 supported by a base ring 14. Suitably secured to the oppositesides of the housing 12 are the lower ends of vertical columns 16.Extending between the upper ends of the columns 16 is a horizontalbridge member 18 provided with opposed pairs of lateral arms 20. Mountedat the outer end of each of the four arms 20 is a vertical pneumaticpiston and cylinder assembly 22 which includes a cylinder 24, astabilizer sleeve 26 and a piston rod 28.

A cylindrical collar 30 is mounted at the upper end of the housing 12 bymeans of an annular inclined wall 32. Also mounted in the housing 12 isa main drive motor 34 operatively connected to a conventional speedreducer unit 36 supported in the collar 30. The output shaft of thespeed reducer 36, in a known manner, is connected to, and serves toeffect rotation of, a generally horizontal polishing wheel assembly 38shown in FIGS. 2 and 3.

The polishing wheel assembly 38 is comprised of an annular backing wheel40 and a polishing cloth 42 extending across the upper face thereof. Thebacking wheel 40 is preferably formed of a metal, such as brass, havinga high heat conductivity. The polishing cloth 42, which may for examplebe either sail cloth or a synthetic nonwoven cloth, is retained inposition by means of a ring or hoop member 44 suitably clamped about theouter periphery of the backing wheel 40. In place of cloth, a feltmaterial may be either clamped to the backing wheel 40 or glued thereon.The polishing wheel assembly 38 is surrounded by an annular thin-walledshroud or shield 46 which is normally maintained in the position shownin FIGS. 1 and 2 to accommodate loading and unloading of the polishingmachine, and is adapted to be raised to the position shown in FIG. 3during polishing operations.

A freely flowing polishing slurry is adapted to be fed to the polishingwheel assembly 38 by tubes or spouts 48 extending downwardly from thebridge member 18 as shown in FIG. I. The slurry is delivered to thespouts 48 through tubing 50 connected to a sump pump unit 52 located inthe lower portion of the housing 12. The polishing slurry flowing fromthe polishing wheel assembly 38 is collected by the inclined wall 32,which serves as a drip pan, and is directed to a drain. The polishingslurry may, by way of example, comprise a polishing compoundsuch as onehaving an abrasive base of iron oxide, cerium oxide or zirconiumoxidesuspended or mixed in water.

Secured in the lower end of each of the piston rods 28 is a verticalspindle assembly 54 comprised of a spindle 56. Each spindle 56 isprovided with a first axial passageway 58 and a second axial passageway60. The first passageway 58 at its lower end is open and at its upperend communicates with a radial inlet 62 which is adapted to be connectedto a source of fluid under pressure. The second passageway-60 at itslower end is closed by a plug 64, intermediate of its ends opensoutwardly of the spindle 56 through a radial aperture 66, and at itsupper end communicates with a radial outlet 68 which is adapted to beconnected to a fluid reservoir or drain. The first passageway 58 andinlet 62 define first passageway means, the second passageway 60 and theaperture 66 and the outlet 68 define second passageway means, and theaforesaid first and second passageway means together define fluidtransmission means for a purpose to be presently described.

Connected to each of the spindles 56 intermediate 0f the ends thereof isa generally horizontal annular pressure cup 70 having engagement meansin the form of an annular ridge 72 at the lower surface thereof.Provided between the spindle 56 and the pressure cup 70 is a floating orswivel connection in the form of a universal ball bearing assembly 74'.The bearing assembly 74 is maintained in assembled position by asnapring 76 engaged in the spindle 56,-and by a snapring 78 engaged inthe pressure cup 70. Suitably secured to the spindle 56 immediatelyabove the pressure cup 70 is a collar assembly 80 which serves to shieldthe bearing assembly 74 from polishing mixture and other foreignmaterial Associated with each pressure cup 70 is a generally horizontalcircular load plate unit 82 which, as shown in FIGS. 3, 4 and 5, iscomprised of upper and lower plate sections 84 and 86 secured togetherby means of a plurality of bolts 88. The upper plate section 84 isformed with a central opening 90, a plurality of radial channels 92which together with the lower plate section 86 define first radial portmeans, a plurality of inclined radial ports 94 which define secondradial port means, and an annular recess 96 which together with anannular recess 97 formed in the lower plate section 86 defines anannular chamber. The ports 92 and 94 and the chamber 96 together definepassageway means in the load plate unit 82. Mounted within the chamber96 for dividing the same into upper and lower sections in communicationat their outer peripheries is an annular baffle panel 98. A plurality ofupwardly and downwardly projecting dimples 100 are formed in the panel98 and serve to center the panel within the chamber 96.

Mounted within the central opening 90 of the load plate unit 82 are apair of vertically spaced seal assemblies 102. Each seal assembly 102comprises an outer body portion 104, and a flexible inner lip portion106 which is biased radially inwardly by a garter spring 108. The lowerend section of the spindle 56 is adapted to be received in the centralopening 90 of the load plate unit 82. in this cooperative position, thefirst passageway 58 in the spindle 56 communicates with the bottomportion of the central opening 90 and the radial ports 92, while theaperture 66 in the spindle 56 communicates with the central opening 90and the radial ports 94 intermediate of the seal assemblies 102. Thegarter springs 108 serve to maintain the flexible lip portions 106 ofthe seal assemblies 102 in engagement with the adjacent periphery of thespindle 56, and the seal assemblies 102 and associated garter springs108 serve as rotary pressure seal means. The upper surface of the upperplate section 84 is provided with engagement means in the form of anannular recess 110 which is adapted to receive the annular ridge 72 ofthe pressure cup 70, while the lower surface of the lower plate section86 is adapted to have affixed thereto work pieces 112.

Referring now to FIGS. 6 and 7, there is indicated generally by thereference numeral 120 a workpiece-mounting device which is adapted to bepositioned on a work bench at a location remote from the polishingmachine 10. The mounting device 120 includes a generally horizontalhousing 122, and an upstanding rectangular frame 124 supported thereon.Secured to the lower leg of the frame 124 is a circular support assembly126 having a central upstanding nose portion 128. The plate assembly 126is formed with first passageway means 130 which at one end opens at theupper end of the nose portion 128 and at the other end communicates withan inlet opening 132 adapted to be connected to a source of fluid underpressure. The plate assembly 126 is also provided with second passagewaymeans 134 which at one end opens at the side of the nose portion 128 andat the other end communicates with an outlet opening 136 adapted to beconnected to a fluid reservoir or drain. The nose portion 128 is ofsubstantially the same size as the lower end sections of the spindle 56,and is adapted to be received in the central opening 90 of a load plateunit 82. Mounted on the upper leg of the frame 124 is a verticalpneumatic piston and cylinder assembly 138 which includes a cylinder 140and a piston rod 142 on the lower end of which is mounted a pressureplate 144.

In preparation for polishing, a load plate unit 82 is positioned on thesupport plate assembly 126 of the workpiecemounting device 120 as shownin FIGS. 6 and 7. A hot fluid medium such as water or steam is thendirected through the inlet opening 132, the first passageway means 130,the passageway means of the load plate unit 82, the second passagewaymeans 134, and the outlet opening 136. Next, a thin layer of paraffin,or other suitable mounting substance,

having a melting point lower than the temperature of the fluid beingcirculated through the load plate unit, is evenly applied to the exposedsurface of the load plate unit. workpieces 112 are then positioned inthe softened liquified paraffin with the sides of the workpieces to bepolished facing upwardly (FIG. 8). To establish an even coating ofparaffin between the workpieces 112 and the load plate unit 82, thepiston rod 142 may be distended for urging the pressure plate 144downwardly from the position shown in solid lines in FIGS. 6 and 7 tothe position shown in dotted lines in FIG. 6 for applying pressure tothe workpieces 112. While pressure is being applied to the workpieces112, circulation of hot fluid through the support plate assembly 126 andthe load plate unit 82 is discontinued, and a fluid coolant such as coldwater is circulated through the assembly 126 and unit 82 for solidifyingthe paraffin and affixing the workpieces 112 to the unit 82. Finally,the pressure plate 144 is retracted upwardly, circulation of coolant isdiscontinued, and the load plate unit and workpieces afiixed thereto areremoved from the mounting device 120 and inverted for transfer to thepolishing machine 10.

At the polishing machine 10, load plate units 82 and workpieces 112affixed thereto are moved onto the polishing wheel assembly 38 andpositioned beneath the respective pressure cups 70. The pneumaticassemblies 22 are actuated to distend the piston rods 28 and the spindleassemblies 54 downwardly until the ridges 72 of the pressure cups 70 areengaged under the desired pressure in the recesses 110 of the load plateunits 82. At the same time, the lower end sections of the spindles 56are received in the central openings of the load plate units 82.

Next, the polishing wheel assembly 38 is rotated and polishing materialis delivered from the spouts 48 to the surface thereof. Also, a fluidcoolant such as cold water is admitted under pressure into the spindleinlet 62, and is transmitted by the first passageway 58 to the bottomportion of the central opening 90 in the load plate unit 82. From theopening 90, the coolant passes through the radial ports 92, around thebaffle panel 98 within the chamber 96, through the radial ports 94, andis returned to the central opening 90 intermediate of the sealassemblies 102. From this point, the fluid is transmitted through thespindle aperture 66 and the second passageway 60, and is discharged atthe spindle outlet 68. In this manner, the coolant absorbs heat byconduction from the load plate unit 82, and the load plate unit isthereby cooled to offset the heat developed therein during the polishingoperation. As workpieces are being polished, the spindles 56 andpressure cups 70 serve to center the load plate units 82, and thebearing assemblies 74 and the seal assemblies 102 accommodate freerotation and floating or swiveling of the load plate units 82.

Upon completion of the polishing operation, drive of the polishing wheelassembly 38, and delivery of polishing material thereto, areinterrupted; the introduction of fluid under pressure into the spindleinlet 62 is interrupted; and the spindle assemblies 54 are retracted andthe pressure cups 70 withdrawn from engagement with the load plate units82. Then, the load plate units 82 and workpieces affixed thereto areremoved from the polishing wheel assembly 38, inverted, and transferredback to the workpiece-mounting device 120. Hot fluid is circulatedthrough the load plate unit 82 for softening the paraffin whereupon theworkpieces are released and become readily removable.

The diameter of each load plate unit 82 may be substantially the sameas, less than, or greater than, the radial width of the annular surfaceof the backing wheel 40. Also, it will be appreciated that in thedrawings certain elements-for example, the cloth 42 and workpieces112-have been exaggerated from the true scale for sake of clarity ofillustration.

While there has been shown and described a preferred embodiment of thepresent invention, it will be understood by those skilled in the art.hat various rearrangements and modifications may be mace thereinwithout departing from the spirit and scope of the invention.

We claim:

1. In a polishing machine having framework, a polishing wheel assemblymounted on the framework on a vertical axis, means for rotating thepolishing wheel assembly, at least one vertical spindle assemblysupported from the framework above the polishing wheel assembly, agenerally horizontal circular load plate unit adapted to have workpiecesaffixed to the lower surface thereof for engagement with the polishingwheel assembly, and means for selectively establishing interengagementbetween the spindle assembly and the load plate unit, the improvementwhich comprises said load plate unit having a central opening, said loadplate unit having passageway means communicating with said opening toaccommodate circulation of fluid interiorly of said unit for effectingcooling thereof, and said spindle assembly having fluid transmissionmeans for separately directing fluid to and receiving fluid from saidopening, said passageway means comprising an annular chamber, firstradial port means intermediate said centralopening and said annularchamber for directing fluid to said chamber, and second radial portmeans intermediate said annular chamber and said central opening forreceiving fluid from said chamber.

2. The improvement of claim 1 including means dividing said chamber intoupper and lower sections in communication at their outer peripheries;and wherein said first radial port means extends between said centralopening and the inner periphery of said lower chamber section, and saidsecond radial port means extends between the inner periphery of saidupper chamber section and said central opening.

3. The improvement of claim 1 wherein said spindle assembly has a lowersection that projects into said central opening, said fluid transmissionmeans comprises first passageway means in said spindle assembly which isadapted to be connected to a source of fluid under pressure andcommunicates with said central opening adjacent said first radial portmeans, and said fluid transmission means further comprises secondpassageway means in said spindle assembly which communicates with saidcentral opening adjacent said second radial port means and is adapted tobe connected to a fluid reservoir.

4. The improvement of claim 3 wherein said interengagement means iscomprised of swivel connection means, and including axially apaced sealmeans in said opening between said lower section of said spindleassembly and said load plate unit on opposite sides of said secondradial port means.

5. For use in a polishing machine, a circular load plate unit having acentral axial opening at one side of said unit, and having passagewaymeans communicating with said opening to accommodate circulation offluid interiorly of said unit, said passageway means comprising anannular chamber, first radial port means intermediate said centralopening and said annular chamber for directing fluid to said chamber,and second radial port means intermediate said annular chamber and saidcentral opening for receiving fluid from said chamber.

6. The load plate unit of claim 5 including means dividing said chamberinto upper and lower sections in communication at their outerperipheries; and wherein said first radial port means extends betweensaid central opening and the inner periphery of said lower chambersection, and said second radial port means extends between the innerperiphery of said upper chamber section and said central opening.

7. The load plate unit of claim 6 including axially spaced flexible sealmeans in said opening on opposite sides of said second radial portmeans.

1. In a polishing machine having framework, a polishing wheel assemblymounted on the framework on a vertical axis, means for rotating thepolishing wheel assembly, at least one vertical spindle assemblysupported from the framework above the polishing wheel assembly, agenerally horizontal circular load plate unit adapted to have workpiecesaffixed to the lower surface thereof for engagement with the polishingwheel assembly, and means for selectively establishing interengagementbetween the spindle assembly and the load plate unit, the improvementwhich comprises said load plate unit having a central opening, said loadplate unit having passageway means communicating with said opening toaccommodate circulation of fluid interiorly of said unit for effectingcooling thereof, and said spindle assembly having fluid transmissionmeans for separately directing fluid to and receiving fluid from saidopening, said passageway means comprising an annular chamber, firstradial port means intermediate said central opening and said annularchamber for directing fluid to said chamber, and second radial portmeans intermediate said annular chamber and said central opening forreceiving fluid from said chamber.
 2. The improvement of claim 1including means dividing said chamber into upper and lower sections incommunication at their outer peripheries; and wherein said first radialport means extends between said central opening and the inner peripheryof said lower chamber section, and said second radial port means extendsbetween the inner periphery of said upper chamber section and saidcentral opening.
 3. The improvement of claim 1 wherein said spindleassembly has a lower section that projects into said central opening,said fluid transmission means comprises first passageway means in saidspindle assembly which is adapted to be connected to a source of fluidunder pressure and communicates with said central opening adjacent saidfirst radial port means, and said fluid transmission means furthercomprises second passageway means in said spindle assembly whichcommunicates with said central opening adjacent said second radial portmeans and is adapted to be connected to a fluid reservoir.
 4. Theimprovement of claim 3 wherein said interengagement means is comprisedof swivel connection means, and including axially apaced seal means insaid opening between said lower section of said spindle assembly andsaid load plate unit on opposite sides of said second radial port means.5. For use in a polishing machine, a circular load plate unit having acentral axial opening at one side of said unit, and having passagewaymeans communicating with said opening to accommodate circulation offluId interiorly of said unit, said passageway means comprising anannular chamber, first radial port means intermediate said centralopening and said annular chamber for directing fluid to said chamber,and second radial port means intermediate said annular chamber and saidcentral opening for receiving fluid from said chamber.
 6. The load plateunit of claim 5 including means dividing said chamber into upper andlower sections in communication at their outer peripheries; and whereinsaid first radial port means extends between said central opening andthe inner periphery of said lower chamber section, and said secondradial port means extends between the inner periphery of said upperchamber section and said central opening.
 7. The load plate unit ofclaim 6 including axially spaced flexible seal means in said opening onopposite sides of said second radial port means.